Light-emitting diodes (LEDs) are increasingly popular for lighting systems for a variety of reasons. The reasons may include greater light produced per unit of power supplied to the LED (compared, for example, to incandescent bulbs), and controllability of the LEDs. The increased popularity of LEDs is also true for the automotive industry.
At least in the context of the automotive industry, LEDs are controlled by controlling average current through the LEDs. However, currently available LED controllers exhibit wide operating frequency swings as the LED voltages vary. That is, as LEDs are switched in and out of operation, such as turning on and off LEDs that provide “high beam” lights for a car, the voltage across the LEDs as a group may swing which causes significant changes in operating frequency of the LED controller. The significant changes in operating frequency make electrical noise and electromagnetic interference (EMI) difficult to suppress.